AC Hissing Sound: Should You Be Worried?

Air conditioners are bound to make strange noises, but not all noise is good to hear. Air conditioners contain a variety of parts that all work together to produce cool air for your home. If you hear an AC hissing sound coming from your unit, something isn't working quite right. 

Let's dive into why air conditioners make hissing sounds and when to call for professional AC service.

For AC repair service in Lexington, KY, let our professionals at Watson Heating & Air take care of it! Call us at 859-695-3950 for expert HVAC service by experienced contractors.

What Causes AC Hissing Sounds?

Because so many components make up your air conditioning system, a hissing sound could come from several parts. However, not all sounds coming from your AC warrant immediate assistance.

Refrigerant Leaks

If you hear a hissing sound coming from your air conditioning unit, it is most likely a refrigerant leak. The sound comes from the refrigerant escaping as a gas, creating a hissing noise. Always contact a professional right away to avoid health concerns from the leaking gas.

Another sign your AC may be leaking refrigerant is warm air coming from your vents. Air conditioners require refrigerant to produce cool air, so if your system is leaking this coolant, your unit will blow warm air. You may also notice a bubbly noise from refrigerant leaks or frost collecting on the outside of your unit. 

Refrigerant leaks cause your unit to work harder, which strains the other components of your air conditioner, likely causing other issues to arise. Once other parts of your air conditioner break due to the strain, the repair cost will go up, so call an HVAC professional right away.

Leaky Ducts

If the AC hissing sound is not coming directly from your outdoor unit, you may have a leaky air duct. Air ducts exist in the walls of your home to transport cool air to various rooms. The leak may be difficult to pinpoint, so call an experienced AC repair company to find and patch the leaky duct.

Valve Leaks

Valves control the pressure of your air conditioner's refrigerant. If you have a valve leak, the hissing noise will be constant and could even grow louder as the unit releases more refrigerant. 

Air conditioners also contain a thermostatic expansion valve that helps release refrigerant pressure. Thermostatic expansion valves should make a hissing noise as the pressure releases, but the sound should not be constant. Valve leaks produce a constant release of pressure. If this is the case, call a certified professional to inspect your unit. 

Heat Pump Valve

The heat pump is in charge of pumping heat in or outside the unit to control the temperature of your home. The heat pump flips back and forth, sometimes causing the pump to malfunction by getting stuck. This creates a constant hissing sound outside of your home. 

Compressor Issues

Compressors move coolant through refrigerant lines and into the system. If your air conditioner has a leak or pressure built up, the compressor will have to work harder to cool your home and could break, causing a loud hissing sound. If this is the case, turn your unit off immediately and call a professional. Some units have a system to prevent pressure from building up in your compressor. When this happens, your unit will shut off, and you will not hear the sound. If your compressor is the issue, contact an expert for help.

When Should You Contact a Professional?

All the individual parts of your air conditioning unit work together. If one part leaks, other parts will begin experiencing issues as well, costing you more money out of pocket. 

It is always best to contact a certified, licensed professional to work on your air conditioning unit. Some problems, such as refrigerant gas leaks, cause health hazards such as nausea and vomiting. Take care of your AC hissing sound by contacting an HVAC expert. Even if you do not hear a hissing sound and your unit is functioning properly, routine maintenance helps deter unexpected issues. 

Call Watson Heating and Air Today!

If you want to know the reasons for the smell from AC or have any questions about the AC hissing noise coming from your unit, let our trustworthy professionals at Watson Heating & Air help you out. We know how to fix the problem as efficiently as possible and in a cost-effective manner. Stop worrying and call us today at 859-695-3950!